Land reclamation in the Netherlands has a long history. As early as in the 14th century, the first reclaimed land had been settled. Much of the modern land reclamation has been done as a part of the Zuiderzee Works since 1919.
According to a 2007 study by Calvin College Michigan (USA), about 65% of the country would be under water at high tide if it were not for the existence and the country's use of dikes, dunes and pumps. Land reclamation in the 20th century added an additional to the country's land area. Of the country's population, 21% lives in the 26% of the land located below mean sea level.
History and origins of land reclamation in the Netherlands
The Netherlands has a coastline that is constantly changing with erosion caused by wind and water. The Dutch people inhabiting the region had at first built primitive dikes to protect their settlements from the sea. In the northern parts of the Netherlands sea levels fell exposing new land at a rate of 5–10 meters per year between 500 BC and 500 AD. This natural process was exploited to claim new agricultural lands. Discontinuous dikes were built to protect the new farms.
Smaller strips of land were reclaimed by filling with sand or other types of land materials. This was usually done near urban and harbour areas since the 14th century. For instance, Amsterdam and Rotterdam were expanding in this manner.
The development of using windmills for pumping water in the 15th century allowed the draining of significant bodies of water. This resulted in the creation of polders. The first steam powered water mill was put to use in 1787.
Polders
The Netherlands is frequently associated with polders, as its engineers became noted for developing techniques to drain wetlands and make them usable for agriculture and other development. This is illustrated by the saying: "God created the world, but the Dutch created the Netherlands"
The Dutch have a long history of reclamation of marshes and fenland, resulting in some 3,000 polders nationwide. About half the total surface area of polders in north-west Europe is in the Netherlands. The first embankments in Europe were constructed in Roman times. The first polders were constructed in the 11th century.
As a result of flooding disasters, water boards called waterschap (when situated more inland) or hoogheemraadschap (near the sea, mainly used in the Holland region) were set up to maintain the integrity of the water defences around polders, maintain the waterways inside a polder, and control the various water levels inside and outside the polder. Water boards hold separate elections, levy taxes, and function independently from other government bodies. Their function is basically unchanged even today. As such they are the oldest democratic institution in the country. The necessary cooperation among all ranks to maintain polder integrity gave its name to the Dutch version of third way politics—the Polder Model.
The 1953 flood disaster prompted a new approach to the design of dikes and other water-retaining structures, based on an acceptable probability of overflowing. Risk is defined as the product of probability and consequences. The potential damage in lives, property and rebuilding costs is compared to the potential cost of water defences. From these calculations follows an acceptable flood risk from the sea at one in 4,000–10,000 years, while it is one in 100–2,500 years for a river flood. The particular established policy guides the Dutch government to improve flood defences as new data on threat levels becomes available.
List of polders
Some famous Dutch polders and the year they were laid dry are: Beemster (1609–1612) Schermer (1633–1635) Haarlemmermeerpolder (1852) As part of the Zuiderzee Works: Wieringermeerpolder (1930) Noordoostpolder (1942) Flevopolder (1956–1966)
Proposed developments
The Markerwaard is the name of a proposed polder in the IJsselmeer that was never built. The construction of Markerwaard would have resulted in the near-total reclamation of the Markermeer. Markerwaard was expected to be finished in 1978.